Sketch the E-R diagram for each of the following situations (if you believe which you need to make extra assumptions, clearly define them for each situation): A university has the large number of courses in its catalog. Attributes of COURSE include Course_Number (identifier), Course_Name, and Units. Each course may have one or more different courses as prerequisites, or may have no prerequisites. Similarly, the particular course may be prerequisite for any number of courses, or may not be prerequisite for any other course. Give the good definition of COURSE. Why is your definition a good one?